ArticleProceedings of the National Academy of Sciences of the United States of America2013
Hammondia hammondi, an avirulent relative of Toxoplasma gondii, has functional orthologs of known T. gondii virulence genes.
Article in Proceedings of the National Academy of Sciences of the United States of America, 2013. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 30 papers.
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Who cites it
30 citing papers in PubMed.
- Toxoplasma gondii and the Brain: Frenemies? Or Just Outright Foes?Journal of the Pediatric Infectious Diseases Society · 2025Review
- Analytic Approaches in Genomic Epidemiological Studies of Parasitic Protozoa.Transboundary and emerging diseases · 2024Review
- A transcriptional network required for bradyzoite development in Toxoplasma gondii is dispensable for recrudescent disease.Nature communications · 2023Article
- AInternational journal of molecular sciences · 2022Article
- A novel fragmented mitochondrial genome in the protist pathogenGenome research · 2021Article
- A real-time quantitative polymerase chain reaction for the specific detection of Hammondia hammondi and its differentiation from Toxoplasma gondii.Parasites & vectors · 2021Article
- Strain-specific disruption of interferon-stimulated N-myc and STAT interactor (NMI) function byParasitology · 2020Article
- Head-to-head comparisons of Toxoplasma gondii and its near relative Hammondia hammondi reveal dramatic differences in the host response and effectors with species-specific functions.PLoS pathogens · 2020Article
- Cell type- and species-specific host responses to Toxoplasma gondii and its near relatives.International journal for parasitology · 2020Review
- A Comparison of Stage Conversion in the Coccidian ApicomplexansFrontiers in cellular and infection microbiology · 2020Review
- Generation of Toxoplasma gondii and Hammondia hammondi Oocysts and Purification of Their Sporozoites for Downstream Manipulation.Methods in molecular biology (Clifton, N.J.) · 2020Article
- Serological diagnosis of Toxoplasma gondii: analysis of false-positive IgG results and implications.Parasite (Paris, France) · 2020Article
- Effector variation at tandem gene arrays in tissue-dwelling coccidia: who needs antigenic variation anyway?Current opinion in microbiology · 2018Review
- A Toxoplasma gondii locus required for the direct manipulation of host mitochondria has maintained multiple ancestral functions.Molecular microbiology · 2018Article
- Dissection of theeLife · 2018Article
- Distribution and Evolution of Peroxisomes in Alveolates (Apicomplexa, Dinoflagellates, Ciliates).Genome biology and evolution · 2018Article
- A Gene-Based Positive Selection Detection Approach to Identify Vaccine Candidates UsingFrontiers in genetics · 2018Article
- Genomics of apicomplexan parasites.Critical reviews in biochemistry and molecular biology · 2017Review
- Importance of serological cross-reactivity among Toxoplasma gondii, Hammondia spp., Neospora spp., Sarcocystis spp. and Besnoitia besnoiti.Parasitology · 2017Review
- Article
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7 authors.
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Abstract
Toxoplasma gondii is a ubiquitous protozoan parasite capable of infecting all warm-blooded animals, including humans. Its closest extant relative, Hammondia hammondi, has never been found to infect humans and, in contrast to T. gondii, is highly attenuated in mice. To better understand the genetic bases for these phenotypic differences, we sequenced the genome of a H. hammondi isolate (HhCatGer041) and found the genomic synteny between H. hammondi and T. gondii to be >95%. We used this genome to determine the H. hammondi primary sequence of two major T. gondii mouse virulence genes, TgROP5 and TgROP18. When we expressed these genes in T. gondii, we found that H. hammondi orthologs of TgROP5 and TgROP18 were functional. Similar to T. gondii, the HhROP5 locus is expanded, and two distinct HhROP5 paralogs increased the virulence of a T. gondii TgROP5 knockout strain. We also identified a 107 base pair promoter region, absent only in type III TgROP18, which is necessary for TgROP18 expression. This result indicates that the ROP18 promoter was active in the most recent common ancestor of these two species and that it was subsequently inactivated in progenitors of the type III lineage. Overall, these data suggest that the virulence differences between these species are not solely due to the functionality of these key virulence factors. This study provides evidence that other mechanisms, such as differences in gene expression or the lack of currently uncharacterized virulence factors, may underlie the phenotypic differences between these species.
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